Such a device is known. It is fitted, for example, to a watch displaying both the date and the day of the week. In this watch, the date and day of the week are set by means of a stem capped by a crown. When the stem is pulled into a first position and the crown is rotated in a first direction, the date is corrected. From this same pulled out position, the day of the week is corrected by rotating the crown in a second direction, opposite to the first. These functions are obtained by means of a sliding pinion meshing with the stem and driving either the date-ring, or the day-disc depending on the rotational direction of the crown.
If the device described hereinbefore gives entire satisfaction for the stated functions, it has a major drawback if it is implemented in a watch comprising for example a date and a timer, the latter allowing the countdown and display on a dial of a predetermined time interval. Indeed, when passing from the calendar date-setting to the desired time-setting of the timer, or vice-versa, the time displayed by the timer is upset or disturbed, this disturbance being caused by the sliding pinion which is not introduced or is removed from the wheel set that it drives along an appropriate direction.